1. Field of the Invention
The present invention relates to a honeycomb structure and an exhaust gas purifying device.
2. Description of the Related Art
Exhaust gas including the particulate matter which mainly has carbon is discharged from vehicles such as buses, trucks and so on; internal combustion engines such as machines for construction; and diesel engines in particular. However, the impacts on the environment and human health caused by the particulate matter have become problems recently. Form example, various compounds are adsorbed in the particulate matter which mainly has carbon, so that the impact on health of the human body by such an adsorbed compounds is a concern.
In such circumstances and based on studies, a filter in which the particulate matter in the exhaust gas is captured so as to purify the exhaust gas, especially a filter with several honeycomb structures composed of porous ceramic is proposed.
For example, several filters comprising honeycomb structures composed of several rectangular-pillar shaped cells that are adjacent across a porous cell wall where each cell elongates longitudinally are proposed. For the honeycomb structure, either end of the cell is sealed with plug for each cell. When the exhaust gas introduced in the honeycomb structure is discharged from the honeycomb structure, the exhaust gas passes through the cell wall. For the filter having such a structure, when the exhaust gas passes though the cell wall, the particulate matter in the exhaust gas is captured (JP 2002-219319A).
Also, in order to convert harmful chemical ingredients such as CO, HC, NOx and so on included in the exhaust gas by means of a catalyst component, after a catalyst carrying layer that is provided on a surface of the cell wall elongates longitudinally in the honeycomb structure, the catalyst is adhered on the catalyst carrying layer. As in the above, such a honeycomb structure is proposed (JP 2002-357114A).
The contents of JP 2002-219319A and JP 2002-357114A are incorporated herein by reference in their entirety.